Problem: Complete the equation. $\dfrac{3}{10} ~=~$
Solution: Let's figure out how many times we add $\dfrac{1}{10}$ to make $\dfrac{3}{10}$. $\dfrac{0}{10}$ $\dfrac{1}{10}$ $\dfrac{2}{10}$ $\dfrac{3}{10}$ $\llap{{+}}\!\frac{1}{10}$ $\llap{{+}}\!\frac{1}{10}$ $\llap{{+}}\!\frac{1}{10}$ $=\overbrace{{\dfrac1{10}} +{\dfrac1{10}} + {\dfrac1{10}} }^{{3}\text{ tenths}} $ $=\dfrac{{3}\times{1}}{{10}}$ $\dfrac{3}{10}=3 \times \dfrac{1}{10}$